:root {
  --color-change: red;  //--color-change  ：变量名，css3有规则
}
$color: var(--color-change); //用var来盛放变量名
.color {
  background-color: purple;
}
$theme: #2CCE85;
// $gold: #ccc;
$gold: $theme;
$phone: $theme;
